Official says separatists had missile systems capable of bringing down aircraft.

KIEV—Ukraine's counterintelligence chief says that Ukrainian separatists were in possession of three medium-range missile systems capable of bringing down commercial or military aircraft, but the rebels shipped these missile systems back to Russia hours after the Malaysia Airlines flight was shot down.

Intelligence compiled by Ukrainian spies show that the three Buk-M1 systems were shipped out of eastern Ukraine on flatbed trucks in two waves in the early morning of July 18, according to Vitaly Nayda, who heads the...